The present invention relates to an elastic tubing pump and more particularly to an elastic tubing pump which is capable of shifting elastic tube by a certain specified length in order to change the position of the elastic tube to be squeezed by pressing rollers and thereby preventing the elastic tube from being worn under the repeated compressive stress.
An elastic tubing pump is a device that draws fluid into an elastic tube and delivers the same therethrough by successively compressing the tube in the direction of the delivery. The elastic tubing pump, by virtue of its ability to transfer any fluid, mainly liquid, and not to destroy living cells has been more and more widely used in medical treatment as for example in the artificial purification of blood through dialysis and also in the fields of biotechnology. However, since in the usual device, repeated compression is applied to the same portion of the elastic tube over a period of time, the tube may easily be prematurely worn and unuseable over a long period of time. Consequently, it has been necessary to replace the elastic tube with new one after a specified time of pumping operation.
In order to solve the above-mentioned problem, the present applicant has previously proposed, based upon the fact that the elastic tube being used as clamped in place and not moveable in the pumping direction, to unclamp the elastic tube after a certain time has elapsed to allow the tube to move past the length of its fatigued portion and then to be compressed at a new unused portion.
The above-mentioned elastic tubing pump is able to move the elastic tube for periodically changing its used portion for a new portion by which the decrease in the reliability of the pump may be restored and, furthermore, the elastic tube can be used continuously over its full length. Accordingly, the cost of the elastic tubing pump may be kept low. There remains the problem that, when the tube is released from the clamper and shifted, the relative moving speeds of the elastic tube and rollers are decreased and therefore the rate of flow may be decreased and become incorrect.